The invention relates to an endoprosthesis for part of the pelvis having at least one base element which can be secured to a resected iliac bone and at least one hip shell attachable at a spacing thereto, with the base element having a first neck which in particular projects at an angle α from the orthogonal to a planar connection surface and the hip shell having a second neck which in particular projects at an angle β from its polar axis.
There are some tumor patients where the ilium, i.e. half the pelvic bone, has to be resected from below by one-third to two-thirds of its height. Without further aid measures, it was previously customary to amputate the associated leg in order to avoid complications due to a lack of attachment to the trunk. To avoid such amputations, endoprostheses for part of the pelvis have been developed which may not be put under excessive strain, but which exert at least a passive retainer function for the leg attached to it.
Such an endoprosthesis is shown in the patent application WO 88/01491 in which two necks are molded to a hip shell and each have a receiving bore for a spigot with a self-locking fixed fit. The spigots are each anchored at their other end to the resected ilium or pubic bone. The anchoring to the ilium in this process takes place via a plate-shaped base element.
A further endoprosthesis of this kind is known from the patent application EP 0 628 294 A1. Receiving bores for spigots having a self-locking fit are provided at a neck of a hip shell. The securing of a shaft part continuing the spigot takes place by intramedullary engagement into a groove milled into the stub of the ilium. A mechanical adjustment unit is additionally provided with the aid of which the shaft part can be adjusted in an elongate bore of a base element secured to the ilium.
It is, however, a disadvantage with the aforesaid endoprosthesis for part of the pelvis that the length of the spigot and the angular position of the spigot are fixedly predetermined relative to the base element and thus also the position and the alignment of the hip shell. The desired position of the hip bone must therefore already be taken into account on the resection of the iliac bone with respect to the height and direction of the resection incision.